​America minted more new millionaires in 2017 than any year since 2010, according to a new report.

Last year, 411,000 U.S. households joined the club of millionaires--the biggest jump in number of households with more than $1 million in investable assets since 2010, the first full year after the recession ended. Investable assets include stocks, bonds, annuities, cash and retirement and education accounts, but exclude real-estate holdings.

There were 7.2 million millionaire households in 2017, about 1 in 17 families in the U.S., according to a report from market-research firm Phoenix Marketing International.

Millionaire households control about 60% of all liquid assets in the U.S., according to the Rhinebeck, N.Y., firm's annual accounting America’s wealthy. The increase in millionaire households mainly reflects strong gains in the stock market last year.

Among states, the highest concentration of millionaires lived in Maryland for the sixth straight year. (See full state rankings below).

But the fastest growth occurred in the West. The number of millionaire households in Washington state grew by almost 10% in 2017.

"It’s more impressive because they’re somewhat on their own, away from the Boston-New York-Washington corridor where a lot of wealth is generated,” said David Thompson, managing director of the affluent practice at Phoenix.

Bridgeport, Conn., and San Jose, Calif., tied for highest share of millionaire households among metro areas, at 9%.

Among smaller towns, known as micropolitan areas, Los Alamos, N.M., topped the list, with 1 in 9 households having at least $1 million. The area boasts many highly paid scientists from a national laboratory there, and a very small population otherwise.

Towns near affluent playgrounds of Park City, Martha’s Vineyard and Jackson Hole also had a high concentration of millionaires, as did energy hubs such as Williston, N.D., and Gillette, Wyo.